Traditional bicycle seats are saddle-shaped and put all of the cyclist's weight on the pubic tubercle and ischiopubic ramus of the pelvis. The recent literature cites increasing reports by cyclists, amateurs and professionals alike, who suffer adverse effects therefrom. Typical adverse experiences, caused by pressure induced by the currently designed saddle-shaped bicycle seat resulting in blunt trauma to the perineal and pelvic structures, suffered include the following symptoms: groin numbness or paresthesia, penile numbness or paresthesia, immediate impotence, delayed impotence, inability to ejaculate or experience orgasm, or the possible correlation with an elevated prostate specific antigen score.
The horn of the saddle designed seat fits directly against the before mentioned pelvic structures. This results in occlusion of arteries and veins supplying blood flow to the penis, as well as, compression of local nerves as they are sandwiched between the horn of the bicycle seat and the bony structures of the anterior pelvis. The resultant outcome is a numbing effect or paresthesia, as reported by many cyclists, that can result in sustained paresthesia of the groin and penis, delayed or immediate impotence, and perhaps even an elevated prostate specific antigen.
Many scientific studies are known to have considered this problem. One study by K. V. Andersen and G. Bovim, entitled "Impotence and Nerve Entrapment in Long Distance Amateur Cyclist" published in Acta Neuro Scandinavia in 1997 provides the results of questioning 160 male Norwegian bicyclists following a 540 kilometer bicycle touring race for symptoms of peripheral nerve compression after long distance cycling.
The gist of the article is that (1) twenty two (22%) percent of the responding males reported symptoms from the innervation areas of the pudendal or cavernous nerves. Thirty-three males had penile numbness or paresthesia; (2) ten of those had numbness that lasted for more than one week; and (3) impotence was reported by 21 or thirteen (13%) percent of the males which lasted more than one week in eleven subjects and for more than one month in three subjects. They concluded that the frequency of impotence and penile numbness may be higher than indicated and the symptoms may last for as long as eight months following blunt trauma to the peripheral nerves.
B. D. Weiss in the Nontraumatic Injuries in Amateur Long Distance Bicyclists, which appeared in the American Journal of Sports Medicine of Mar. 13, 1985, at pages 187 to 192, reports the questioning 132 participants in a 500 mile 8-day bicycle tour to determine the frequency and severity of nontraumatic injuries experienced by riders. The cyclists rode an average of 95.8 miles per week on a routine basis. Following the race, they found the most nontraumatic injury to be buttock pain experienced by 32.8% of the riders. Groin numbness and paresthesia occurred in approximately 10% of the participants.
F. J. Levine, A. J. Greenfield, and I. Goldstein in their article "Arteriographically Determined Occlusive Disease Within the Hypogastric-Cavernous Bed in Impotent Patients Following Blunt Perineal and Pelvic Trauma", which appeared in the Journal of Urology 1990; Volume 144, Number (5) at Pages 1147-1153; reported on the presence, location, and pattern of arterial occlusive disease within the hypogastric-cavernous arterial bed in impotent men following blunt perineal and pelvic trauma. They reviewed internal pudendal arteriogram of 20 patients with a history of blunt perineal trauma and seven with blunt pelvic trauma, who immediately developed of impotence. Arteriographic studies of 104 other impotent patients were reviewed for a comparison.
Patients who had suffered blunt pelvic and perineal trauma had significantly different patters of arteriographically demonstrated occlusive disease within the distal hypogastric-cavernous arterial bed consistent with the site of traumatic injury. Those who sustained blunt pelvic trauma and had immediate impotence revealed arterial occlusive lesions mainly in the internal pudendal, common penile, cavernous, and dorsal arteries. Those who sustained blunt penile trauma and complained of immediate impotence demonstrated a more focal pattern of pathological arterial occlusion primarily in the cavernous and dorsal arteries. Those with blunt perineal trauma demonstrated a significantly higher incident of solitary arterial lesions in the cavernous artery without proximal disease than those with blunt pelvic trauma, 48% and 8%, respectively.
They hypothesized that blunt trauma without immediate impotence may be a potential risk factor for the late development of arterial vasculogenic impotence, and that unrecognized or seemingly innocuous trauma may be a factor in cases of idiopathic impotence. Patient without trauma and vascular factors have more diffuse patterns of arteriographically demonstrated arterial lesions.
L. A. Mathews, T. E. Herberner, and A. D. Seftel, in their article, "Impotence Associated with Blunt Pelvic and Perineal Trauma; Penile Revascularization as a Treatment Option", which appeared in the papers of the Seminar on Urology in 1995, Chapter 13 Volume 1, Pages 66-72; also recognized erectile dysfunction or impotence as a well-known complication from blunt pelvic and perineal trauma. The mechanism of injury is usually related to the trauma itself through the shearing of the penile vasculature in the pelvis or by direct trauma to the vasculature in the perineum.
R. M. Munarriz, Q. R. Yan, A. Znehra, D. Udelson, and I. Goldstein in their article, "Blunt Trauma: The Pathophysiology of Hemodynamic Injury Leading to Erectile Dysfunction" which appeared in the Journal of Urology of 1995 Volume 153, Number 6 at Pages 1831-1840, reported on blunt trauma as it relates to the pathophysiology of the hemodynamic injury leading to erectile dysfunction. Out of 131 men studied, corporeal veno-occlusive dysfunction was identified in 62% of the cases and cavernous artery insufficiency in 70% . Patients with pelvic trauma had significantly more abnormal sites of venous drainage and more sever degrees to which venous structures filled with contrast media when observe with arteriography. Pharmaco-arteriography revealed the site specific arterial occlusive lesions that were consistent with the site of impact.
Traumatic vasculogenic impotence is hypothesized to be the result of direct injury to the proximal corpora and its arterial inflow bed. Traumatic veno-occlusive dysfunction is theorized to be the consequence of focal intracavernous wound repair and permanent focal alterations in erectile tissue compliance. They reported that traumatic vasculogenic impotence afflicts and estimated 600,000 American men of whom 250,000 have sports-related injuries.
A. Rana and G. D. Chisholm, in their article "He Sold His Bike for a Low Prostate Specific Antigen", which appeared in the Journal of Urology 1994, Volume 151, Number 3 at Page 700, describe an individual who holds his bicycle seat on an exercise bicycle responsible for an elevated prostate specific antigen (PSA). The 80 year old patient quit exercising on that seat, resulting in a drop from a clinical stage T3 adenocarcinoma of the prostate and a PSA of 3,244 milligrams per milliliter at the time of diagnosis. The patient usually rides his exercise bicycle every morning for 1 to 2 miles. On the presumption that the activity is causing the marked increase in his PSA, he was instructed to decrease his exercise.
With the decreased use of his exercise bicycle, and no treatment for his adenocarcinoma, his PSA consistently decreased. After 24 months, the patient ceased all bicycle riding and his PSA was decreased to 5.9 milligrams per milliliter. The riding of his exercise bicycle with the standard miniaturized saddle exerts a direct pressure on the perineum and prostate. They reported that the high PSA levels were consistent with the massaging action of the bicycle seat on the prostatic tumor.
H. R. Safford, D. E. Craford, S. H. Mackenzie, and M. Capriola, in their article, "The Effect of Bicycle Riding on Serum Prostate Specific Antigen Levels", which appeared in the Journal of Urology 1996, Volume 156, Number 7 at Pages 103 to 105, reported on the effect of bicycle riding on serum prostate specific antigen levels. They obtained baseline PSA levels from 260 volunteers before completing a 250 mile bicycle race. After the 4 day race, PSA was remeasured and the level was compared to the pre-race levels. They found no statistically or clinically significant elevation in the PSA after bicycle riding. However, those with an initially elevated PSA had an increase after bicycle riding, although the change did not represent the population. More research is needed on this topic.
Most recently Dr. Irvin Goldstein, a leading Urologist and pioneer in the surgical treatment of impotence at the Boston Medical Center, was featured on the Sep. 18, 1997 edition of 20/20 entitled Men, Biking, and Impotence. One of his conclusions is that numbness in the groin may be the first warning sign of impending impotence or the inability to have an erection. Another part of his data shows that six out 100 men in his practice can trace back the cause of impotence to bicycling. The theory behind this is that all of the person's weight is supported by the artery to the penis and has confirmed this by finding artery blockage in the exact position where the bicycle seat fits a mans crotch. Dr. Goldstein has determined that just 11% of a man's weight can cause compression of the penile arteries as they press on the bicycle seat. The injury is typically bilateral as the pressure from the ischiopubic ramus of the pelvis compresses the penile arteries against the bicycle seat.
The penile arteries normally bounce back from episodes of compression but with repeated and extended injury they could cause permanent damage to the vessel walls leading to blockage of blood flow resulting in impotence. According to Dr. Goldstein, this repeated trauma causes hardening and flattening of the arteries much like that caused by hypertension and cigarette smoking. This repeated insult to the vessels over time can lead to delayed impotence. He reported that 52% of men in the United States are impotent. He estimates that there are approximately 100,000 men that have become impotent from damage inflicted by bicycle seats. He boldly stated that he would not ride a bicycle with its seat in the present design form.
Thus it proper to conclude that there is a major problem with bicycle seat design. This problem requires an effective solution.